hwmon: New subsystem maintainers

Guenter Roeck volunteered to adopt the hwmon subsystem as long as he
wasn't the only maintainer. As this was also my own condition, we can
add the two of us as co-maintainers of the hwmon subsystem.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>